With world leaders gathered in Paris to find a solution on climate change, Pope Francis said the stakes could not be any higher. The pope said the human race is on the "limits of suicide." (Reuters)

Environmental negotiators meeting in Paris should strike a climate change deal to save a world "at the limits of suicide," Pope Francis said on Monday.

"I am not sure, but I can say to you 'now or never'," he told a group of reporters aboard the papal plane, en route home from Africa, according to Reuters. "Every year the problems are getting worse. We are at the limits. If I may use a strong word I would say that we are at the limits of suicide."

The comments come at the start of a United Nations-sponsored environmental summit in Paris, which nearly 150 world leaders are expected to attend.